This invention relates to a fluid flow regulator, and in particular to an adjustable fluid flow regulator having a pressure-responsive diaphragm.
Prior art regulators used an orifice positioned under a flexible diaphragm, which moved up and down to provide a means of regulating pressure through the orifice. Such regulators achieved less than desirable stability, due to the cyclic opening and closing of the orifice opening. The regulator disclosed in Pernat et. al., U.S. Pat. No. 4,651,778 attempts to improve stability with a diaphragm having a pin protruding into an orifice opening, for varying the size of the flow area as the diaphragm moves up and down. However, Pernat discloses a pin concentrically assembled within a diaphragm, not within an orifice. Manufacturing tolerances can cause the diaphragm and pin to be misaligned with the orifice, compromising the control of uniform flow area through the orifice. Thus, there is a need for an improved regulator device having a means of reliably controlling the flow area through an orifice opening for regulating pressure.
The present invention relates to an improved regulator construction that isolates the function of a pressure-responsive diaphragm from the function of a flow-restricting pin in an orifice. The present invention utilizes a tapered pin disposed within an orifice, as opposed to prior regulators having a pin affixed to a diaphragm that is positioned over an orifice. The tapered pin centers itself, and does not encounter any side forces associated with a diaphragm and pin that are misaligned with the orifice. This provides for more precise movement and control of flow area, as well as better sealing against the orifice. The regulator construction of the present invention provides an improved means for reliably controlling the flow area through an orifice opening to achieve a more stable regulation of flow.
The tapered pin construction of the present invention further includes a biasing spring. The biasing spring biases the tapered pin in a direction away from the orifice in which it is disposed, and towards a pressure-responsive diaphragm. The pressure-responsive diaphragm is able to move freely, independent of any lateral movement by the tapered pin. The tapered pin moves relative to the bore of the orifice that it centers itself in, under the influence of the pressure-responsive diaphragm. Thus, the pressure-responsive diaphragm""s movement is unaffected by any misalignment of the diaphragm with respect to the tapered pin and orifice, and the tapered pin""s movement is unaffected by any diaphragm movement not in line with the bore of the orifice.